DESCRIPTION: (Adapted from applicant's abstract.) Acquired color vision defects have been reported in many visual disorders, but the underlying causes for these defects have rarely been evaluated with quantative color vision models. Recent studies have applied color vision models both to psychophysical data from normal human observers and to neurophysiological data from single-unit recordings in the primate retina and thalamus. The long-term goals of the proposed research are to apply such models to analysis of acquired color vision defects, in order to provide a better understanding of the alterations in cone function and in postreceptoral processing, the relation between disease progression and color vision defects, and the potential contributions of color vision testing within treatment trials. The emphasis in the current five-year proposal is on applying quantitative color vision models to analysis of acquired color vision defects in patients with retinitis pigmentosa (RP) or primary open-angle glaucoma (POAG), two populations for which acquired color vision deficits have frequently been reported, and for which damage is known to occur primarily at the photoreceptor level (RP), or the retinal ganglion cell level (POAG). This study will provide a better understanding of the mechanisms of visual loss in RP and POAG. The insights gained from this analysis will in the long run be useful for investigation of other diseases for which the cellular pathophysiology is less well understood.